WordPress 3.4 – paging problem

I got the following problem after updating to wp-3.4 for my theme:

My front page displays is “Your latest posts”. So my index/home page is a list of recent posts with pagination. (www.test.com)

the pagination works with ajax/jquery. So if someone hits the “next” buttons (url = http://www.test.com/?paged=2) jquery loads the content and insert this without refreshing the page (.load function).

Problem: Since 3.4. the .load function gives no result. Apperently the .load function loads a “blank page” OR “no page”.
But typing the url (…/?paged=2) manually in the browser works fine. The secong page is shown.

What I’ve have so far:
…/?p=1&paged=2 -> works
…/?paged=2 -> doesn’t work
…/paged/2/ -> doesn’t work

first it seams to be a jquery coding issue but why is …/?p=1&paged=2 working then?? I have no idea why it’s not working with the …/?paged=2
And on 3.3.2 it was working fine, so it has something to be with wordpress.

Does anyone have an idea?